Process for the preparation of polymer fibers

Abstract

Polymeric fibers are produced from a polymer-solvent solution without mechanical agitation means by supplying a polymer solution in a solvent to a radial-symmetrical mixing chamber and causing a rotary flow therein which subjects the polymer to shearing forces while, at the same time, adjusting the temperature of the polymer-solvent mix to just below the precipitation temperature of the polymer. Under these conditions a polymeric fiber precipitates which, after separation from the solvent, is useful in the preparation of paper and textile products.

What is claimed: 
     
       1. A continuous process for preparing polymer fibers by concurrent precipitation and agitation of a fiber-forming polymer solution comprising the steps of: a. preparing a solution of a fiber forming polymer by dissolving the polymer in a solvent therefor;   b. continuously supplying the thus-formed polymer solution to a radial symmetrical chamber;   c. continuously supplying a precipitant for said polymer to said radial-symmetrical chamber in an amount and at a temperature such that the temperature of the polymer solution-precipitant mixture is below the precipitation temperature of said polymer;   d. subjecting the introduced polymer solution to shearing forces by creating within said radial symmetrical chamber a rotary flow causing said polymer in the polymer solution to precipitate in a fibrous structure and form fibers under said shearing forces;   e. continuously removing the fibers and solvent as a mixture from the chamber;   f. separating and collecting the fibers from the solvent; and   g. recycling at least a portion of the fiber free solvent to the rotation chamber after conforming the recycle temperature to the temperature of the flow in the rotation chamber.   
     
     
       2. The process according to claim 1 wherein said fiber-forming polymer is an alpha-alkene having 2-6 carbon atoms. 
     
     
       3. The process according to claim 1 wherein the temperature of the solvent in said chamber is about 5° to about 15° C below the precipitation temperature of said polymer in said solvent. 
     
     
       4. The process according to claim 1 wherein the fiber-forming polymer solution is mixed with the precipitant prior to step (b). 
     
     
       5. The process according to claim 1 wherein the fiber-forming polymer solution is mixed with the precipitant during step (b) by continuously supplying the precipitant to the rotation chamber in a tangential direction with respect to the rotary flow in the chamber. 
     
     
       6. The process of claim 1 wherein the fiber-forming polymer solvent and the precipitant are the same. 
     
     
       7. A process for preparing polymer fibers by the concurrent pecipitation and agitation of a fiber-forming polymer in solution comprising the steps of: a. continuously supplying a solution of a fiber-forming polymer in a solvent therefor at a temperature of about 5 to about 15 centigrade degrees below the precipitation temperature of said polymer in said solvent to a rotary flow of solvent and polymer contained and rotating within and about the axis of a radial-symmetrical rotation chamber, said solution being supplied to said chamber in direction tangential to said rotary flow and under pressure such that it passes through said chamber in a rotary flow, thereby causing said polymer to precipitate in a fibrous structure and form fibers while under the influence of shearing forces in said rotary flow;   b. continuously removing said fibers and said solvent as a mixture from said chamber along the axis thereof;   c. separating said fibers from said mixture of step (b);   d. recycling at least a portion of said solvent to said chamber and adjusting the temperature of said recycled solvent, prior to introduction into said chamber, to the temperature of the solution of step (a).   
     
     
       8. In a process for preparing polymer fibers by concurrent precipitation and agitation of a fiber-forming polymer in a solvent therefor including the steps of mixing said polymer solution with a precipitant therefor in an amount and at a temperature such that the temperature of the resulting mixture is below the precipitantion temperature of the polymer, the improvement comprising introducing the polymer-solution-precipitant into a radial-symmetrical chamber in a tangential direction with respect to the rotary flow in the chamber and subjecting the thus introduced solution to shearing forces within the chamber while concurrently precipitating the polymer from the solution, thereafter removing the thus precipitated polymer in the form of fibers together with solvent, separating the fibers from the solvent and recycling at least a portion of the recovered solvent to the radial-symmetrical chamber.